3-Aminopyridine → N-3-Pyridinylurea

Temperature

-10 °C

Benzoyl isocyanate (3.28 g, 22.3 mmol, 1.05 equiv.) was taken up in CH2Cl2 (30 mL) and cooled to −10° C. Pyridin-3-amine (2 g, 21.2 mmol, 1 equiv.) was added in portions while stirring. The mixture was allowed to stir for 3 h at room temperature. After the reaction was deemed complete, it was concentrated and then taken up in a 1:1 mixture of CH3OH and H2O (100 mL) followed by the addition of NaOH (4.25 g, 106.3 mmol, 5 equiv.). The reaction was allowed to stir overnight at room temperature, concentrated to dryness, and then azeotroped three times with toluene. A mixture of 10% CH3OH in EtOAc (100 mL) was added to the solid and stirred for 10 minutes followed by filtration. The solid was suspended and filtered two additional times. The combined filtrates were filtered once more to remove any solids that passed through the filter and concentrated. The residue was triturated with EtOAc (5 mL) and dried under vacuum to yield 3.5 g of crude material (off-white solid) that was utilized without further purification. LC/MS: m/z (ES+) 138 (M+H)+.

1. stirringto stir for 3 h at room temperature
2. concentrationit was concentrated
3. additiontaken up in a 1:1 mixture of CH3OH and H2O (100 mL)
4. stirringto stir overnight at room temperature
5. concentrationconcentrated to dryness
6. customazeotroped three times with toluene
7. additionA mixture of 10% CH3OH in EtOAc (100 mL)
8. additionwas added to the solid
9. stirringstirred for 10 minutes
10. filtrationfollowed by filtration
11. filtrationfiltered two additional times
12. filtrationThe combined filtrates were filtered once more
13. customto remove any solids that
14. filtrationfilter
15. concentrationconcentrated
16. customThe residue was triturated with EtOAc (5 mL)
17. customdried under vacuum

ORD record

ord-ff7e877ff89b4dca8065c495a122fa1b

Source dataset

uspto-grants-2015_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09181200B2